Evidence-Based Medicine

Articles tagged with "Evidence-Based Medicine".

Cold Water Swimming: Benefits and Risks Narrative Review

Tags: Cold Therapy, Research Review, Evidence-Based Medicine

January 16, 2026

Is Cold Water Swimming Safe and Beneficial?

Yes, when done properly by healthy, experienced people. This narrative review found that regular cold water swimming brings health benefits including improved blood markers, stronger immunity, better mood, and general well-being. However, there’s a real risk of death for inexperienced swimmers from cold shock or hypothermia.

Cold water swimming has a long tradition in northern countries like Finland, Poland, Russia, and the Nordic nations. What was once practiced by only extreme athletes has evolved into a popular sport with international competitions. This 2020 review examines the evidence for both benefits and dangers.

Cold-water Immersion: Neurohormesis and Possible Therapeutic

Tags: Neurology, Cold Therapy, Research Review, Evidence-Based Medicine

January 16, 2026

Can Cold Water Therapy Benefit Your Brain?

Yes, the science suggests it can. This 2024 review from The Journal of Neuropsychiatry explains how cold water immersion triggers “neurohormesis,” a process where mild stress creates beneficial effects on the brain and nervous system. Cold exposure releases key brain chemicals and may even protect against neurodegenerative diseases.

Hormesis is an important concept in biology: low doses of stress can actually help the body, while high doses cause harm. Cold water immersion (typically 10-15°C) produces this controlled stress, triggering a cascade of beneficial responses throughout the body and brain. This review examines the evidence for cold water’s effects on mental health and neurological function.

Core Physiology: Diving Reflex, Trigeminal Pathways, Autonomic Control

Tags: Cold Therapy, Research Review, Evidence-Based Medicine

January 16, 2026

What Is the Diving Reflex and Why Does It Matter?

The diving reflex is a powerful survival response found in all mammals, including humans. When triggered by water immersion, especially cold water on the face, your heart rate can drop by up to 80% while blood flow redirects to protect your brain and heart. This ancient reflex may hold the key to understanding cold water’s effects on health.

The mammalian diving response overrides normal body functions to preserve life during underwater submersion. First studied in seals and dolphins, researchers now know this reflex exists in all vertebrates. Laboratory rats show this response 100% of the time when submerged. Understanding this reflex helps explain why cold water therapy affects the body so profoundly.

Editorial: The Trigeminocardiac Reflex Beyond the Diving Reflex

Tags: Cardiovascular Health, Cold Therapy, Research Review, Evidence-Based Medicine

January 16, 2026

What Is the Trigeminocardiac Reflex and Why Does It Matter?

The trigeminocardiac reflex (TCR) is the most powerful autonomic reflex in humans and mammals. This editorial summarizes nearly 20 years of research showing that stimulating the trigeminal nerve (which runs through your face) triggers immediate heart rate changes. Understanding this reflex has implications far beyond surgery, including sleep disorders and sudden infant death syndrome.

First described in neurosurgical settings in 1999, the trigeminocardiac reflex has been extensively studied for its effects during skull base surgery. Now researchers are expanding their understanding to explore how this reflex might play a role in various health conditions and potentially lead to new treatments.

Effects of Adding Facial Immersion to Chest-level Water Immersion

Tags: Cold Therapy, Research Review, Evidence-Based Medicine

January 16, 2026

Does Putting Your Face in Water Boost the Benefits of Water Immersion?

No. This 2025 study found that adding facial immersion to chest-level water immersion did not increase heart rate variability beyond what chest immersion alone provides. While standing in water up to your chest significantly boosted vagal tone, putting your face in the water added no extra benefit.

Researchers from Germany tested whether combining two known relaxation triggers would produce a stronger effect. Standing in water up to your chest activates your vagus nerve through water pressure on your body. Putting your face in water triggers the diving reflex. Would doing both at once double the benefits? The answer was no.

Effects of Cold Stimulation on Cardiac-vagal Activation and Hrv

Tags: Cardiovascular Health, Cold Therapy, Clinical Trial, Evidence-Based Medicine

January 16, 2026

Can Applying Cold to Your Neck Reduce Stress?

Yes. This randomized controlled trial found that cold stimulation to the lateral neck significantly increased heart rate variability and decreased heart rate, suggesting activation of the body’s relaxation response. The neck region showed the strongest effect compared to the cheek and forearm.

Researchers from the University of Luxembourg wanted to find out if localized cold exposure could trigger the body’s calming vagus nerve. They were exploring the potential for a wearable device that could help people reduce stress in real-time. The results suggest the lateral neck is an effective target area.

Exercise Recovery, Doms, and Training Adaptation

Tags: Exercise Recovery, Cold Therapy, Evidence-Based Medicine

January 16, 2026

Does Cold Exposure Hurt Your Thinking Ability?

Yes. This systematic review of 18 studies found that cold exposure impairs brain function in 15 out of 18 experiments. The most affected areas were attention, processing speed, memory, and executive function.

Researchers wanted to know how cold air and cold water affect mental performance in healthy adults. They looked at studies using climate chambers and cold water tanks. The findings have important implications for workers in cold environments, such as fishermen, soldiers, and mountain rescuers.

Exploratory Study Into Effects of Regular Cold-water Swimming On

Tags: Mental Health, Cold Therapy, Evidence-Based Medicine

January 16, 2026

Does Cold Water Swimming Improve Your Mood the Same Day?

Yes. This diary study found that regular cold water swimmers had significantly lower anxiety and higher self-confidence on days when they swam compared to days when they didn’t. These benefits even carried into the next morning with better sleep and lower anxiety.

Researchers used a twice-daily diary method to track 13 female cold water swimmers in the UK over a two-week period. This is the first study to capture the immediate, same-day effects of cold water swimming rather than measuring changes over months.

Exploring the Use of Sea Swimming in Youth Mental Health Services

Tags: Mental Health, Cold Therapy, Evidence-Based Medicine

January 16, 2026

Can Sea Swimming Help Young People with Mental Health Challenges?

Yes, according to this qualitative study from Ireland. Young people in mental health services reported improved well-being, increased confidence, and a greater sense of social connection after participating in sea swimming. Staff members acknowledged the risks but emphasized the importance of positive risk-taking given the benefits.

About one-third of young people experience some degree of psychological distress, and 13% experience emotional or mental distress. The COVID-19 pandemic made things worse, with lockdowns and school closures increasing isolation, anxiety, and depression among youth. Researchers in Ireland wanted to understand whether sea swimming could help.

Human Dive Reflex During Consecutive Apnoeas with Facial Immersion

Tags: Cold Therapy, Evidence-Based Medicine

January 16, 2026

Does Full Body Immersion Make the Dive Reflex Stronger?

Not significantly, but it does make the reflex more coordinated. This study had 11 volunteers perform three consecutive 60-second breath-holds with facial immersion, comparing dry conditions versus full-body water immersion. While overall reflex strength was similar, full immersion produced greater heart rate changes and better synchronization between body systems.

The human dive reflex is your body’s oxygen-conserving response during breath-holding and water exposure. Researchers from Charité University in Berlin wanted to know whether being fully submerged in water produces a stronger or better-coordinated reflex compared to just putting your face in water while staying dry.

Improved Mood Following a Single Immersion in Cold Water

Tags: Mental Health, Exercise Recovery, Cold Therapy, Evidence-Based Medicine

January 16, 2026

Can a Single Cold Water Dip Improve Your Mood?

Yes. This study found that just one 18-minute immersion in cold sea water significantly improved mood in 42 healthy adults. Total mood disturbance dropped by 15 points in the cold water group compared to only 2 points in controls.

You don’t need to swim. You don’t need weeks of practice. According to this 2021 study from the University of Chichester, simply standing in chest-deep cold water can produce immediate mood benefits. This challenges the common belief that swimming or exercise is required for cold water’s mental health effects.

Limitations of Facial Immersion as a Test of Parasympathetic Function

Tags: Cold Therapy, Evidence-Based Medicine

January 16, 2026

Is Facial Immersion a Good Test of Vagal Function?

Not as reliable as once thought. This classic study found that facial immersion in water produces variable heart rate responses that aren’t purely controlled by the parasympathetic nervous system. Atropine (which blocks the vagus nerve) failed to reduce the bradycardia in two of three subjects, suggesting other mechanisms are involved.

Researchers have long used facial immersion in cold water to test parasympathetic (vagal) function. The idea is simple: cold water on the face triggers the diving reflex, which slows the heart through vagal activation. But this 1988 study from Brazil’s University of São Paulo found the test is more complicated than it appears.